From the prior art, devices are known, which can be used to determine the friction value between a body and a substrate made of a different material. Also, devices are known from the prior art, which allow determining the friction value (rolling friction) between plastic hollow bodies with the same material composition.
The international patent application WO 2007/094704 A1 discloses a system for automatic control of the friction values of preforms, which are used with a blowing machine for manufacturing plastic bottles. PET plastic bottles are manufactured from said preforms. The system according to the invention allows to control automatically the fraction values between the preforms and to add liquid appropriately based on the determined measured values so that the friction value between the preforms can be set to a specific value. For this purpose, a rotating carrier in a chamber is provided. A specific braking value is measured, which is forwarded to a control station, from where liquid is then appropriately transferred into the chamber.
The British patent application GB 2 187 560 A discloses a device for measuring the surface friction. This device allows determining the friction forces, which occur at the surface of a container. For this purpose, the container is rotated with respect to a thrust impinged with a force. The braking force is measured, which the thrust exerts on a transducer via a lever. This method allows determining the different friction values at a can's periphery depending on the different coloured layers of the can.
U.S. Patent Application 2002/0194895 A1 discloses an analysis system, which allows determining the fraction between two bottles. The device suggested here allows determining the friction coefficient for plastic bottles, which do not have a planar surface. This device allows determining the coefficient of friction of plastic bottles or preforms with each other. For this purpose, a stationary sample contacts a rotating sample. A force is applied onto the stationary sample towards the rotating sample. By means of a computer, the required torque is determined at the time point when both probes slide against each other. Also, the torque amount is determined, which is required to keep a constant speed. Based on the torque measurements, the computer calculates the friction coefficient between both material samples.
Patent specification DD 234 933 A1 concerns a method and an assembly for determining coefficients of adhesion and sliding friction. The test materials are vehicle tires and the track surface acting on the vehicle tires. The test materials are pressed by means of articulated devices onto a friction surface provided for the measurement and shifted by means of gravity with constant contact pressure by mechanically acting equipment's. By shifting the test materials on the friction surface, the vertical pressing force, which acts on the test materials, and the required tractive force required for shifting the test materials are measured for determining the friction values.